IMX6DQ RGMII impedance?

[zhiminwan]

hi,

i'm doing a design using I.MX6DQ.

what's impedance of the RGMII interface in I.MX6 chip?

does it need to add termination resistor on the RGMII tx signals?

I notice the Sabre board does not use them.

but i didn't any information in the datasheet.

thanks

[Yuri · Accepted solution]

Driver strength and ODT of RGMII signals are configurable.

Please refer to section 36.4.487 [Pad Group Control Register

(IOMUXC_SW_PAD_CTL_GRP_RGMII_TERM)] and of the i.MX6 DQ RM.

“Drive strength Controlled by bits [5:3] (DSE) of the following registers

in IOMUXC (IOMUX controller):

IOMUXC_SW_PAD_CTL_PAD_RGMII_TXC

IOMUXC_SW_PAD_CTL_PAD_RGMII_TX_CTL

IOMUXC_SW_PAD_CTL_PAD_RGMII_TDx (4 registers)

IOMUXC_SW_PAD_CTL_PAD_RGMII_RXC

IOMUXC_SW_PAD_CTL_PAD_RGMII_RX_CTL

IOMUXC_SW_PAD_CTL_PAD_RGMII_RDx (4 registers)”

http://cache.freescale.com/files/32bit/doc/ref_manual/IMX6DQRM.pdf

Termination resistors are not recommended.

  Also, please refer to section 9.5.1.2 (RGMII) of the “Hardware Development Guide for i.MX 6 …”
regarding IBIS model.

http://cache.freescale.com/files/32bit/doc/user_guide/IMX6DQ6SDLHDG.pdf

Have a great day,
Yuri

-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------